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Gore Pulls Slide of Disaster Trends

COLELLAPHOTO.COM via AAAS.orgAl Gore addresses the American Association for the Advancement of Science.

Former Vice President Al Gore is pulling a dramatic slide from his ever-evolving global warming presentation. When Mr. Gore addressed a packed, cheering hall at the annual meeting of the American Association for the Advancement of Science in Chicago earlier this month, his climate slide show contained a startling graph showing a ceiling-high spike in disasters in recent years. The data came from the Center for Research on the Epidemiology of Disasters (also called CRED) at the Catholic University of Louvain in Brussels.

The graph, which was added to his talk last year, came just after a sequence of images of people from Iowa to South Australia struggling with drought, wildfire, flooding and other weather-related calamities. Mr. Gore described the pattern as a manifestation of human-driven climate change. “This is creating weather-related disasters that are completely unprecedented,” he said. (The preceding link is to a video clip of that portion of the talk; go to 7th minute.)

Now Mr. Gore is dropping the graph, his office said today. Here’s why.

Two days after the talk, Mr. Gore was sharply criticized for using the data to make a point about global warming by Roger A. Pielke, Jr., a political scientist focused on disaster trends and climate policy at the University of Colorado. Mr. Pielke noted that the Center for Research on the Epidemiology of Disasters stressed in reports that a host of factors unrelated to climate caused the enormous rise in reported disasters (details below).

Dr. Pielke quoted the Belgian center: “Indeed, justifying the upward trend in hydro-meteorological disaster occurrence and impacts essentially through climate change would be misleading. Climate change is probably an actor in this increase but not the major one — even if its impact on the figures will likely become more evident in the future.”

Officials at the disaster center, after reviewing what Mr. Gore showed and said, sent a comment to Dr. Pielke’s blog and to me. You can read their full response below. I sent it to Mr. Gore’s office and asked for his interpretation. Kalee Kreider, Mr. Gore’s spokeswoman on environmental matters, wrote back today:

I can confirm that historically, we used Munich Re and Swiss Re data for the slide show. This can be confirmed using a hard copy of An Inconvenient Truth. (It is cited if you cannot recall from the film which is now several years old!). We became aware of the CRED database from its use by Charles Blow in the New York Times (May 31, 2008). So, it’s a very new addition.

We have found that Munich Re and other insurers and their science experts have made the attribution. I’m referring you particularly to their floods section/report [link, link] Both of these were published in a series entitled “Weather catastrophes and climate change-Is there still hope for us.”

We appreciate that you have pointed out the issues with the CRED database and will make the switch back to the data we used previously to ensure that there is no confusion either with regards to the data or attribution.

As to climate change and its impacts on storms and floods, the IPCC and NOAA among many other top scientific groups have indicated that climate change will result in more extreme weather events, including heat waves, wildfires, storms and floods. As the result of briefings from top scientists, Vice President Gore believes that we are beginning to see evidence of that now.

Reproduced with permission, from Guha-Sapir, D., Vos, F.; Quantifying Global Environmental Change Impacts: Methods, Criteria and Definitions for Compiling Data on Hydro-Meteorological Hazards in Coping with Global Environmental Change, Disasters and Security – Threats, Challenges, Vulnerabilities and Risks. Edited by H. Brauch et al Hexagon Series on Human and Environmental Security and Peace, vol. 5 (Berlin – Heidelberg – New York: Springer-Verlag, 2009).Click on the image for a full-sized version of the graph, which shows storm trends as a green band and flooding and related landslides in blue.

At right is a link to the Belgian center’s graph of disaster trends through 2008 (click to see the whole thing). And here is the center’s statement (highlight added):

CRED is fully aware of the potential for misleading interpretations of EM-DAT figures by various users. This is a risk all public datasets run…. Before interpreting the upward trend in the occurrence of weather-related disasters as “completely unprecedented” and “due to global warming”, one has to take into account the complexities of disaster occurrence, human vulnerabilities and statistical reporting and registering.

Over the last 30 years, the development of telecommunications, media and increased international cooperation has played a critical role in the number of disasters that are reported internationally. In addition, increases in humanitarian funds have encouraged reporting of more disasters, especially smaller events. Finally, disasters are the convergence of hazards with vulnerabilities. As such, an increase of physical, social, economic or environmental vulnerabilities can mean an increase in the occurrence of disasters.

We believe that the increase seen in the graph until about 1995 is explained partly by better reporting of disasters in general, partly due to active data collection efforts by CRED and partly due to real increases in certain types of disasters. We estimate that the data in the most recent decade present the least bias and reflect a real change in numbers. This is especially true for floods and cyclones. Whether this is due to climate change or not, we are unable to say.

Once again, we would like to point out that although climate change could affect the severity, frequency and spatial distribution of hydro-meteorological events, we need to be cautious when interpreting disaster data and take into account the inherent complexity of climate and weather related processes — and remain objective scientific observers.

It’s pretty clear it was the climate-disaster link. There were some things missing from the article, however. As the folks in Belgium explained above, the connection between human-driven climate change and recent trends in disasters remains highly uncertain, even as most climate scientists foresee intensification of floods and droughts and, of course, more coastal flooding with rising sea levels.

So while the climate hook might have given this story its “front-page thought,” there’s no examination in the article of simultaneous trends in population growth in poor places, urbanization (people are leaving marginal lands for many reasons) and the like.

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By 2050 or so, the human population is expected to pass nine billion. Those billions will be seeking food, water and other resources on a planet where humans are already shaping climate and the web of life. Dot Earth was created by Andrew Revkin in October 2007 -- in part with support from a John Simon Guggenheim Fellowship -- to explore ways to balance human needs and the planet's limits.